1. Field of the Invention
This invention generally relates to servers for accessing and storing information from an information network. More specifically, this invention relates redundant power supply management for server systems.
2. Description of the Related Art
There is currently an ever-increasing need to access computerized information networks, such as the Internet. Access providers utilize scalable networks of computer systems, known as server farms, to interface with client computers on the front end, and to access information on behalf of the client from other computer systems on the back end.
Front-end server farms are scaleable by adding or removing modular server systems. Often, the server modules are inserted side-by-side in a rack that includes one or more external power supplies for the server systems. To provide high availability, one or more redundant power supplies are included to deliver power in the event of a power supply failure. That is, if one power supply fails, one or more of the redundant power supplies takes the load without interrupting service.
In known systems, redundancy is commonly achieved by configuring the server farm with an extra power supply. The power output from more than one power supply is bussed through a current sharing circuit such that if one supply fails, enough power is still available on the power bus to effectively power the system.
To provide redundancy, server systems are typically configured with n+1 power supplies, where n is the number of power supplies required to provide power for the maximum system configuration. For example, a scaleable server system may be designed to include from 1 to 4 processors, 3 storage drives, and 3 power supplies (2+1) that supply a total of 825 watts (3xc3x97275 watts). When fully populated, the server system requires 550 watts or less, leaving a spare 275 watts of redundant power. It is, however, possible that the system may be configured with fewer processors and/or disk drives. In this situation, 2 power supplies may be adequate to provide redundancy, with the third power supply being added if and when more components are added to the system. Cost saving may be realized by installing only the number of power supplies necessary to operate the server system while still achieving redundancy and high availability.
It is therefore highly desirable to provide a server system that is capable of determining the power required to supply adequate power to the components as well as to provide redundancy in the event of a failure. It is also desirable for the server system to provide this requirement to the user. It is further desirable for the server system to be able to revise power supply requirements when components are added or removed from the server system.
The present invention provides a system and method that is capable of determining power requirements based on the hardware configuration. A system management bus is coupled to the servers to provide information on power being utilized by the servers during operation. The information from the system management bus is provided to program instructions that provide power usage values indicative of the power being utilized by the servers. The program instructions further determine the maximum value of the power usage values, and determine power supply requirements based on the maximum power usage. The power supply requirements include operating power and/or redundant power requirements.
One feature of the present invention is that it generates a warning signal if adequate power is not available to the servers. This includes operating power and/or redundant power.
Another feature of the present invention is that it detects changes in hardware components in the servers, and determines revised operating and/or redundant power supply requirements when changes are made in the hardware components.
Another feature of the present invention is a set of averaging program instructions to generate a running average of the power usage values. A new running average of the power usage values is determined when a change in the hardware components is detected in the servers.
The present invention advantageously provides a system and method that may be used to accurately determine power supply requirements, so that only as many power supplies as are necessary to achieve the level of redundancy desired by an operator may be included in the system. The present invention provides indications of when a power supply may be added or removed to maintain the level of redundancy desired. This saves cost and complexity, and improves operating reliability.
The foregoing has outlined rather broadly the objects, features, and technical advantages of the present invention so that the detailed description of the invention that follows may be better understood.